Methods and apparatus for mixing and distributing fluids

ABSTRACT

A flow distribution device ( 100 ) has a vane distributor ( 111 ) at least partially disposed within a cartridge ( 102 ) and is operationally coupled to a second distributing device ( 112 ) that receives output from the vane distributor ( 111 ) Especially preferred flow distribution devices ( 100 ) are disposed within a vessel containing a contact bed, and may include at least a second vane distributor ( 112 ) within the cartridge ( 102 ), wherein the vane distributors ( 111, 112 ) are preferably swirl-inducing vane distributors ( 111, 112 ).

FIELD OF THE INVENTION

The field of the invention is fluid mixing and distribution.

BACKGROUND OF THE INVENTION

Many industrial processes involve mixing and distribution of fluids, andproper mixing and homogeneous distribution of fluids is especiallyimportant to ensure economic operation at high throughput rates incatalytic reactors or fractionation columns. However, variousdifficulties typically arise with high volume throughput, and especiallywhere the fluid has multiple phases (e.g., liquid and vapor).Consequently, numerous approaches have been tried to circumvent at leastsome of the problems.

For example, many fixed bed reactors and other vessels with concurrentdownflow of one or more fluid phases employ inlet diffusers. Inletdiffusers are typically located at the inlet nozzle and are generallyconfigured to effect a distribution of the fluid onto a cross-sectionalarea in the vessel below (see e.g., U.S. Pat. No. 3,685,971 to Carson).Where appropriate, inlet diffusers may be utilized in combination withadditional devices, and particularly distribution trays (see e.g., U.S.Pat. No. 3,146,189 to Halik, et al.). While such configurations oftenprovide at least some homogeneous distribution of a liquid over a targetarea, all or almost all of them exhibit significant shortfalls whenvapor and liquid phases need to be homogeneously distributed.

To circumvent at least some of the problems with homogeneousdistribution of vapors and liquids, inlet diffusers may be configured toachieve at least partial disengagement of the entering vapor and liquidphases (see e.g., U.S. Pat. No. 3,378,349 to Shirk, et al., or U.S. Pat.No. 4,579,647 to Smith). Such inlet diffusers, which typically improvehomogeneous distribution of vapor and liquids at least to some degree,are, however, often not satisfactory when the vapor and liquid may enterthe inlet diffuser with significant momentum and in a verynon-homogeneous manner. Vapors and liquids may be homogenized to helpimprove distribution as described, for example, in U.S. Pat. No.4,126,539 to Derr, et al., by providing perforated plates in combinationwith passageways defined by concentric frustoconical sections. However,and especially where the liquid and vapor have a relatively highmomentum, liquid may pass primarily through the orifices located nearthe points where the liquid impacts the perforated plate. Furthermore, anon-uniform vapor velocity profile may result in vapor recirculationzones above the perforated plate, with consequent inhibition of theliquid flow through orifices located below these vapor recirculationzones.

Alternatively, as described in U.S. Pat. No. 3,915,847 to Hutchings, aperforated plate together with a tube sheet and distribution conduitsmay be employed to assist homogeneous distribution of vapor and liquid.However, maldistribution of liquids and vapors may still persist in suchconfigurations due to liquid impingement upon and/or vapor recirculationabove the perforated plate. Moreover, such configurations typicallyinhibit personnel access to a vessel, as such configurations are notreadily withdrawn through the top nozzle of the vessel.

In still other approaches, mixing devices may include a configurationwith chevron-type vanes, wherein the device is disposed between theoutlet of a mixing chamber and an imperforate deck as described incopending U.S. patent application Ser. No. 10/031,856, which isincorporated by reference herein. While such devices typically improvemixing and distribution of liquids and vapors, circumferentiallyasymmetric fluid distribution may still occur, especially when theliquid and vapor stream enters the mixing and distribution deviceasymmetrically.

Thus, although there are numerous mixing and distribution devices knownin the art, all or almost all of them suffer from one or moredisadvantages. Therefore, there is still a need for improved methods andapparatus for mixing and distributing fluids.

SUMMARY OF THE INVENTION

The present invention is directed to methods and configurations of flowdistribution devices that include a vane distributor at least partiallydisposed within a cartridge and operationally coupled to a seconddistributing device that receives output from the vane distributor.

In particularly preferred devices, the vane distributor comprises aswirl-inducing vane distributor, and it is especially preferred thatsuch devices may include a second vane distributor disposed in thecartridge (e.g., fluidly coupled together via a perforated plate),wherein the vane distributor and the second vane distributor areconfigured such that a flow that exits the vane distributor changesdirection before entering the second vane distributor. In furtherespecially preferred devices, the second distributing device is disposedat least partially outside of the cartridge, and the vane distributorhas a plurality of vanes, and wherein at least one vane is positioned atan acute angle relative to a radius of the cartridge.

Various objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of preferred embodiments, along with the accompanyingdrawings in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of an exemplary device comprising fiveswirl-inducing vane distributors, four of which are contained within acartridge, with the swirl direction changing at the inlets to the secondthrough fifth distributors.

FIG. 2 is a perspective view of an exemplary device comprising fiveswirl-inducing vane distributors, four of which are contained within acartridge, with the swirl direction changing at the inlets to the secondand fourth distributors.

FIG. 3 is a perspective view of an exemplary device comprising fiveswirl-inducing vane distributors, all of which are contained within acartridge.

FIG. 4 is a perspective view of a distribution device with chevron-typevanes, disposed between two plates.

DETAILED DESCRIPTION

The inventors have discovered that mixing and distribution devices canbe significantly improved by providing such devices with a vanedistributor that is at least partially disposed within a cartridge andoperationally coupled to a second distributing device that receivesoutput from the vane distributor. The term “fluid” as used in thespecification and claims is meant to include both liquids and gases. Theterm “vapor” and “gas” are used interchangeably herein.

Especially preferred devices will include a swirl-inducing vanedistributor (i.e., a vane distributor in which at least some of thevanes have an orientation such that the vapor/liquid that exits thedistributor will have a rotational momentum) that receives an inputcomprising at least one of a vapor and a liquid, wherein the vaporand/or liquid that exits the distributor is contained within a cartridge(which may or may not be at least in part an integral portion of avessel). Even more preferably, it is contemplated that a second vanedistributor within the cartridge will receive at least a portion of themixed vapor and/or liquid, wherein the first vane distributor and thesecond vane distributor are fluidly coupled together via a perforatedplate.

One particularly preferred device 100 is depicted in FIG. 1 and has acartridge 102 that encloses a first and second swirl-inducing vanedistributor 111 and 112, respectively, wherein the distributors arecoupled together via imperforated plate 120. A separator 130 formstogether with the cartridge 102 an enclosed space 104 that allows fluidcommunication between the first and second distributors 111 and 112, andprevents fluid communication between spaces 104 and 106 in a path otherthan through distributors 112 and 114. Second space 106 (formed byseparator 130 and the cartridge 102) includes distributors 114 and 116,which are separated via plate 120. Additional distributing device 140(preferably a swirl-inducing vane distributor) is disposed outside ofcartridge 102 and in fluid communication with the distributor 116.

In further preferred aspects, the inlets to the vane distributors may besurrounded by a weir (not shown). For example, the inlet to the secondvane distributor 112 may be surrounded by a weir (not shown) and it iscontemplated that the weir may enhance the capacitance for liquidhold-up within enclosed space 104, thereby further promoting mixing andredistribution of fluids flowing through the device. All weir shapes arecontemplated, including straight, V-notch, trapezoidal, andproportional.

It should be appreciated that in the configuration of FIG. 1 the vanesin each distributor are oriented in the same direction, when viewed fromthe cartridge inlet. Consequently, the trajectory of fluid/vapor flowingthrough one distributor must be significantly altered (if not evenreversed) to enter the next (and following) distributor(s). Therefore,it is contemplated that these trajectory changes, induced by the vaneorientation, will promote turbulence, mixing, and redistribution of thefluids.

Alternatively, as depicted in FIG. 2, the vanes of the device of FIG. 1in the first, second, and fifth distributors are oriented in a directionopposite of the vanes in the third and fourth distributors, when viewedfrom the cartridge inlet. Again, the trajectory of fluid/vapor flowingthrough the first and third distributors must be significantly altered(if not even reversed, e.g., from counterclockwise to clockwise) toenter the next distributor. Therefore, it is contemplated that thesetrajectory changes, induced by the vane orientation, will promoteturbulence, mixing, and redistribution of the fluids.

Where it is desirable that the terminal distributor is at leastpartially, and more preferably entirely disposed within the cartridge,the cartridge may be extended to include the terminal (here: fifth)distributor to create an enclosed volume below the terminal distributoras shown in FIG. 3. In further preferred aspects, the cartridge outletmay be surrounded by a weir (not shown). It is contemplated that suchenclosed volume may provide capacitance for liquid hold-up within thecartridge, thereby further promoting mixing and redistribution of fluidsflowing through the device.

Where it is desirable that the terminal distributor is disposed outsidethe cartridge, it should be recognized that the terminal distributor maycomprise various types of vanes, and it is especially preferred that theterminal distributor includes chevron-type vanes or swirl-inducing vanesas depicted in FIG. 4.

It should be especially appreciated that contemplated devices may beemployed to mix and/or homogeneously distribute any gas, vapor, liquid,solid, or reasonable combination thereof. However, particularlypreferred materials include mixtures of vapors and liquids commonlyprocessed in refining and petrochemical plants, and especially materialsthat are fed into a contacting device (e.g., fixed bed catalyticreactor). Consequently, contemplated devices may advantageously beemployed as inlet diffusers. In further especially preferredconfigurations, suitable devices are configured to be removably coupledto a vessel or inlet of a vessel.

In yet further contemplated aspects, it is generally preferred that thepressure drop over the device may be limited at least in part by theangle at which one or more of the vanes are oriented relative to theradius of the distributor. For example, where intimate mixing andsubstantial redistribution is less critical and a low pressure drop ishighly desirable, it is contemplated that the angle of the vanes isbetween 1 and 25 degrees (relative to the radius). On the other hand,where proper mixing and redistribution is required at a relativelymoderate pressure drop (e.g., less than 5 psi), it is contemplated thatthe angle of the vanes is between 26 and 60 degrees (relative to theradius). Furthermore, it should be recognized that the angle of thevanes need not be the same for all of the distributors. However, itshould be recognized that the selected angle(s) for the vanes comprisingeach distributor will also be influenced by the fluid properties, thevelocity of the fluid passing through the device, and other geometricaldimensions of the device.

Thus, specific embodiments and applications for improved mixing anddistribution devices have been disclosed. It should be apparent,however, to those skilled in the art that many more modificationsbesides those already described are possible without departing from theinventive concepts herein. The inventive subject matter, therefore, isnot to be restricted except in the spirit of this specification.Moreover, in interpreting the specification, all terms should beinterpreted in the broadest possible manner consistent with the context.In particular, the terms “comprises” and “comprising” should beinterpreted as referring to elements, components, or steps in anon-exclusive manner, indicating that the referenced elements,components, or steps may be present, or utilized, or combined with otherelements, components, or steps that are not expressly referenced.

1. A flow distribution apparatus comprising a vane distributor at leastpartially disposed within a cartidge and operationally coupled to asecond distributing device that receives output from the vanedistributor, wherein the output comprises a mixture of a vapor and aliquid, wherein the cartridge is at lean partially disposed within avessel, and wherein the flow distribution apparatus distributes themixture of the vapor and the liquid to the vessel.
 2. The flowdistribution apparatus of claim 1 wherein the vane distributor comprisesa swirl-inducing vane distributor.
 3. The flow distribution apparatus ofclaim 1 further comprising a second vane distributor at least partiallydisposed in the cartridge.
 4. The flow distribution apparatus of claim 3wherein the vane distributor and the second vane distributor areconfigured such that a flow that exits the vane distributor changesdirection before entering the second vane distributor.
 5. The flowdistribution apparatus of claim 3 wherein the vane distributor and thesecond vane distributor are coupled together via a perforate deck. 6.The flow distribution apparatus of claim 3 wherein the vane distributorand the second vane distributor art coupled together via an imperforatedeck and the cartridge.
 7. The flow distribution apparatus of claim 1whereen the second distributing device comprises a swirl-inducing vanedistributor or a chevron-type vane distributor.
 8. The flow distributionapparatus of claim 7 wherein the second distributing device is disposedat least partially outside of the cartridge
 9. The flow distributionapparatus of claim 1 wherein the vane distributor has a plurality ofvanes, and wherein at least one vane is positioned in an angle of lessthan 60 degrees relative to a radius of the cartridge.
 10. The flowdistribution apparatus of claim 1 wherein the vessel is a contactor.